Contents

Introduction

This document discusses the configuration for a Cisco Catalyst 3550 Series Switch. You can use any Catalyst 2970, 3560, or 3750 Series Switch in this scenario in order to obtain the same results. The document demonstrates how to configure a MAC access control list (ACL) in order to block communication among devices within a VLAN. You can block a single host or a range of hosts, based on the host network interface card (NIC) adapter manufacturer. You can block a range of hosts if you disallow Address Resolution Protocol (ARP) packets that originate from these devices based on the IEEE Organizational Unique Identifier (OUI) and company_id assignments.

In a network, you can block ARP request packets in order to restrict user access. In some network scenarios, you want to block ARP packets based, not on the IP address, but on the Layer 2 MAC addresses. You can accomplish this type of restriction if you create MAC address ACLs and VLAN access maps and apply them to a VLAN interface.

Prerequisites

Requirements

Components Used

The information in this document is based on the Cisco Catalyst 3550 Switch.

The information in this document was created from the devices in a specific lab environment. All of the devices used in this document started with a cleared (default) configuration. If your network is live, make sure that you understand the potential impact of any command.

Related Products

Other switches that support the commands in this configuration include Catalyst 2970, 3560, or 3750 Series Switches.

Configure

In this section, you are presented with the information to configure the features described in this document.

In order to configure MAC address filtering and apply it to the VLAN interface, you must complete several steps. First, you create the VLAN access maps for each type of traffic that must be filtered. You select a MAC address or range of MAC addresses for blocking. You also need to identify the ARP traffic in the access list. In accordance with RFC 826, an ARP frame uses the Ethernet protocol type of value 0x806. You can filter on this protocol type as interesting traffic for the access list.

In global configuration mode, create a named MAC extended access list with the name ARP_Packet.